Charges that a doctor who treated America's Olympic gymnasts molested a young girl at his home are "the tip of the iceberg," Michigan's attorney general said Tuesday.

Police revealed that about 50 gymnasts and patients of Dr. Larry Nassar have filed sexual abuse complaints against him, but those cases are still under investigation.

For now, Nassar has been charged with three counts of criminal sexual conduct for "predatory, menacing criminal acts involving a minor, a young girl under the age of 13,” AG Bill Schuette said at a press conference.

The alleged abuse took place at Nassar's home in Holt, Michigan, between 1998 and 2005, according to court papers. Authorities said the victim was not a gymnast or a patient but did not detail her relationship to the doctor.

"She was violated and abused when she was just a young girl. Just a child, a little child," Schuette said. "Dr. Nassar stole this victim's childhood, which can never be undone."

Dr. Nassar stole this victim's childhood which can never be undone. As a father that thought is heartbreaking.

Nassar, 53, was arrested Monday at a tire shop. He posted $100,000 bond on Tuesday and was released after pleading not guilty at an arraignment. He faces up to life in prison if convicted.

Outside court, his attorney, Shannon Smith, said she was "disappointed" police arrested Nassar when he had offered to turn himself in. She noted that his wife was in court to support him.

"In fact, there are hundreds of people who support him 100 percent," she told NBC affiliate WILX. "We have received countless e-mails and communications from other doctors, physicians, physical therapists, ex-patients, ex-co-workers supporting him. There's no doubt he has a ton of support."

Smith did not comment on the specific charges but Nassar's legal team has said in the past that any "procedures" he performed were medically appropriate.

Nassar was the team doctor for USA Gymnastics, the sport's governing body, from 1996 to 2015, when he was fired in response to "athlete concerns."

He was also fired by Michigan State University, where he had his sports medicine practice, this fall after the first accusations against him surfaced in the Indianapolis Star.

Since then, dozens of women have filed complaints alleging that Nassar molested them under the guise of invasive medical examinations.

Two women have filed lawsuits against Nassar and USA Gymnastics. One is a former Olympic medalist who says she was molested for several years in the mid-1990s, starting when she was 13. The other was a member of the USA national team, who says famed coaches Bela and Marta Karolyi turned a blind eye to abuse at their training center in Texas.

USA Gymnastics, which has hired an attorney to review the organization's sexual abuse policies, has pointed out that it reported Nassar to the FBI in 2015. It's not clear what was done after that, but federal investigators are involved in the current probe.

John Manly, an attorney representing several of Nassar's accusers, including the two women who have filed suit, called on authorities to expand their probe to include USA Gymnastics and Michigan State.

“We applaud the efforts by Attorney General Schuette to protect children from sexual abuse by filing charges against Dr. Nassar. We strongly encourage The Attorney General and the U.S. Attorney to conduct a full investigation of USA Gymnastics and Michigan State University to determine why they failed to discover, report and stop Nassar’s dangerous and unlawful conduct," he said in a statement.